How do I connect a subwoofa

[VanillaIce220]

Hello.

The last time i installed an audio system was on my first car a subaru RS impreza and I installed the whole thing, headunit, speakers, amp, sub. I have been spending my money on doing a good unit for my lib and finally got a sub. I have installed the headunit, installed a 4 channel focal amp and have the speakers running to the amp because of the mckintosh stock set up(annoying as shit). Basically the fronts have a channel each (1 and 2) and the rears are going into the same channel (3rd), left the forth for the sub. This is probably a really simple question and i probably already answered it myself but I like being certain with what i am doing.

So with the sub I just run the (+) and (-) wire into the amp and away i go right? also the sub i have has 2 of the (+) and 2 of the (-) do i need to run both side into the amp, or only need to do one side?

Thanks.

[mihai]

I'd drop the rears from channel 3 and have the sub bridged across channel 3+4

Having rears on channel 3 and sub on channel 4 will mean that when you apply LPF it will also apply it to the rears and they will sound shit.

Also, depending on the ohmage of the voice coils of the sub will depend how you wire the two + and two - terminals on the sub.

If dual 2 ohm voice coils then id recommend going amp + -> sub +1 , sub -1 -> sub +2, sub -2 -> amp -

If dual 4 ohm voice coils, then you need to make sure that the amp is stable at 2ohm and if it is then you will need to wire the sub + to each other and the sub - to each other. Then amp + and amp - goes to sub + and sub - respectively.
If the amp is not 2 ohm stable, you'll need to wire it as above.